The present invention relates to an ink-jet printhead, and more particularly to an ink-jet printhead provided with a filter for removing foreign matter from ink.
Japanese Patent Application Provisional Publication HEI 9-314836 discloses an ink-jet printhead having a laminated structure and actuated by a piezoelectric actuator on demand. The disclosed ink-jet printhead is constructed from substantially six plates stacked together in a laminated body. Assuming that the uppermost plate is the first plate and the lowermost one the sixth plate, the second plate sandwiched between the first and third plates is formed with a plurality of small openings that function as pressure generating chambers. The fifth plate sandwiched between the fourth and sixth plates is provided with a plurality of large openings that define common ink supply chambers.
The common ink supply chambers are filled with ink supplied from an external ink tank, which ink is then distributed to the plurality of pressure generating chambers through ink channels formed in the third and fourth plates.
Each pressure generating chamber is in fluid communication with a corresponding one of a plurality of nozzle orifices formed in the sixth plate or the lowermost plate. Further, a piezoelectric vibration plate is fixed on the top surface of the first plate so as to selectively compress each pressure generating chamber. When one of the pressure generating chambers is compressed, an ink droplet ejects from the nozzle orifice corresponding to the compressed pressure generating chamber.
The fourth plate is provided with recesses that are formed at areas facing the common ink supply chambers. These recesses isolate vibration generated by the piezoelectric vibration plate.
An ink supply channel is formed in the laminated body of the ink-jet printhead through which ink from the external ink tank flows into the common ink supply chambers. Generally, a separate plate-like filter is attached to the inlet of the ink supply channel for removing foreign matter from the ink flowing into the common ink supply chambers, since such foreign matter might clog up the nozzle orifices of the printhead. The filter is an essential component of the ink-jet printhead. However, it increases the component count of the ink-jet printhead, and also requires additional work for attaching it to the ink-jet printhead.
Therefore, there is a need for an ink-jet printhead that does not require attaching a filter thereto for filtering ink supplied from an external ink tank.